U.S. patent number 9,290,003 [Application Number 14/767,688] was granted by the patent office on 2016-03-22 for inkjet ink containers having oxygen scavenging properties.
This patent grant is currently assigned to PolyOne Corporation. The grantee listed for this patent is PolyOne Corporation. Invention is credited to Roger W. Avakian, John H. Hornickel, Lynn I. Marrs.
United States Patent |
9,290,003 |
Marrs , et al. |
March 22, 2016 |
Inkjet ink containers having oxygen scavenging properties
Abstract
An inkjet ink container is disclosed comprising a polymer
compound comprising an oxygen scavenging composition. The oxygen
scavenging composition is selected from the group consisting of
copolymers of polycondensate segments and oxygen scavenging moiety
segments; oxygen scavenging unsaturated polymers; oxygen scavenging
dendrimers; molecular hydrogen generators; and combinations
thereof.
Inventors: |
Marrs; Lynn I. (El Granada,
CA), Avakian; Roger W. (Solon, OH), Hornickel; John
H. (Medina, OH) |
Applicant: |
Name |
City |
State |
Country |
Type |
PolyOne Corporation |
Avon Lake |
OH |
US |
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Assignee: |
PolyOne Corporation (Avon Lake,
OH)
|
Family
ID: |
51354473 |
Appl.
No.: |
14/767,688 |
Filed: |
January 24, 2014 |
PCT
Filed: |
January 24, 2014 |
PCT No.: |
PCT/US2014/012986 |
371(c)(1),(2),(4) Date: |
August 13, 2015 |
PCT
Pub. No.: |
WO2014/126698 |
PCT
Pub. Date: |
August 21, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150352854 A1 |
Dec 10, 2015 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61764431 |
Feb 13, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D
81/266 (20130101); B41J 2/17553 (20130101); B41J
2/17513 (20130101) |
Current International
Class: |
B41J
2/175 (20060101); B65D 81/26 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 583 727 |
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Feb 1994 |
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EP |
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00/71334 |
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Nov 2000 |
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WO |
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Other References
International Preliminary Report on Patentability for
PCT/US2014/012986. cited by applicant.
|
Primary Examiner: Jackson; Juanita D
Attorney, Agent or Firm: Hornickel; John H.
Parent Case Text
CLAIM OF PRIORITY
This application claims priority from U.S. Provisional Patent
Application Ser. No. 61/764,431 filed on Feb. 13, 2013, which is
incorporated by reference.
Claims
What is claimed is:
1. An inkjet ink container comprising a polymer compound comprising
an oxygen scavenging composition, wherein the oxygen scavenging
composition is selected from the group consisting of: (a)
copolymers of polycondensate segments and oxygen scavenging moiety
segments; (b) oxygen scavenging unsaturated polymers; (c) oxygen
scavenging dendrimers; (d) molecular hydrogen generators; and (e)
combinations thereof.
2. The container of claim 1, wherein the polymer compound comprises
a thermoplastic resin selected from the group consisting of
polyesters, polyamides, polyolefins, polycarbonates, polystyrenes,
polyacrylates, thermoplastic elastomers of all types, and
combinations thereof.
3. The container of claim 2, wherein the polyester comprises
polyethylene terephthalate, polybutylene terephthalate,
polylactides or polyhydroxyalkanoates.
4. The container of claim 1, wherein the inkjet container is a
print cartridge body.
5. The container of claim 1, wherein the inkjet container is an ink
supply container for connection with a print cartridge body.
6. The container of claim 1, wherein the container is an ink supply
container of any size or shape in which inkjet ink is stored before
association with an inkjet printer.
7. The container of claim 6, wherein the container is an ink supply
container of ink in bulk.
8. The container of claim 1, wherein the oxygen scavenging
composition scavenges for (a) oxygen molecules within the volume of
the container not occupied by the ink, (b) oxygen molecules within
walls of the container, and (c) oxygen molecules permeating through
the container walls.
Description
FIELD OF THE INVENTION
The invention concerns inkjet cartridges and reservoirs made from
polymer materials including oxygen scavenging functional
additives.
BACKGROUND OF THE INVENTION
Spoilage of food has plagued humanity for millennia. Containers for
food have evolved from stone to ceramic to metallic to glass to
plastic, particularly for single serving consumable foods and
beverages.
Shelf life of foods and beverages is affected by oxidation from
oxygen molecules within the volume of the container not occupied by
the food or beverage ("headspace oxygen"), within the bulk of the
container walls ("inherent oxygen"), and permeating through the
container walls or closure ("permeated oxygen"). Also the food or
beverage itself contains oxygen which equilibrates in the
headspace.
Packaging of food or beverages has utilized oxygen scavenging
compositions to help preserve the freshness from oxidation by
headspace oxygen, inherent oxygen, and permeated oxygen. Any food
or beverage, medicament or cosmetic, or any other material highly
reactive with oxygen molecules can benefit from this invention.
Shelf life of food and other perishable materials can be extended
because of the presence of the oxygen scavenging composition,
preferably activated by a catalyst at an appropriate time.
The ColorMatrix Corporation is a leader in the supply of oxygen
scavenging compositions to the food and beverage industry
worldwide.
SUMMARY OF THE INVENTION
Inkjet printing ink is another material which can be reactive with
oxygen molecules.
What the art needs is an inkjet cartridge, reservoir, or other
container to have the benefit of oxygen scavenging.
The present invention solves the problem in the art by utilizing
polymer compounds containing oxygen scavenging compositions, which
compounds are shaped into containers of any size already used or
useful in the delivery of inkjet ink.
For purposes of this invention, "container" means a vessel of any
size or shape in which inkjet ink is stored before association with
an inkjet printer, such as a storage container of ink in bulk, or
after association with an inkjet printer, such as an inkjet
cartridge in its holder in a desktop printer or a larger reservoir
associated with a commercial scale large format inkjet printer.
One aspect of the present invention is an inkjet ink container
comprising a polymer compound comprising an oxygen scavenging
composition.
An advantage of oxygen scavenging inkjet ink containers related to
cost reduction is that the amount of packaging protection for the
cartridge, which typically uses an expensive foil lined or
multi-layer film to protect the cartridge from O.sub.2 exposure,
can be eliminated or reduced in complexity and cost. For example,
oxygen barrier tie layers might be eliminated or reduced in number
in foil or multi-layer film packaging for inkjet ink cartridges. An
additional benefit is that such packages will be easier to
open.
Other advantages of the invention are mentioned in connection with
various embodiments.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic diagram of one printing system including a
printing fluid supply system according to U.S. Pat. No. 5,818,484
(Lee et al.)
FIG. 2 is a perspective view illustrating a print cartridge body
according to an embodiment of U.S. Pat. No. 6,851,800 (Seu).
FIG. 3 is a bottom perspective view of the print cartridge body of
FIG. 2.
EMBODIMENTS OF THE INVENTION
Inkjet Containers
Any container as defined above is a candidate for use in the
present invention. What qualifies a container to be a candidate is
that it is made of a polymer compound, it is intended to contain
inkjet ink for any duration, and it benefits from the addition of
an oxygen scavenging composition.
Non-limiting examples of inkjet containers include inkjet
cartridges such as those disclosed in U.S. Pat. No. 6,851,800
(Seu); U.S. Pat. No. 6,030,075 (Swanson et al.); U.S. Pat. No.
5,745,137 (Schefflin et al.); and U.S. Pat. No. 5,594,483
(Kaplinsky et al.); all of which are incorporated by reference
herein as if fully rewritten in their entirety.
Using U.S. Pat No. 6,851,800 as one embodiment of an inkjet
cartridge, Seu discloses a single-piece print cartridge body having
a plurality of outlet ports disposed along a single axis that is
substantially perpendicular to a direction of motion of the print
cartridge body during printing. First and second compartments are
respectively communicatively coupled to first and second cavities.
The first and second cavities are substantially parallel to the
single axis and are located on opposite sides of the single axis. A
first channel interconnects the first cavity and a first one of the
plurality of outlet ports. A second channel interconnects the
second cavity and a second one of the plurality of outlet ports.
The first and second channels are substantially perpendicular to
the single axis. In another embodiment, a third compartment is
connected to a third one of the plurality of outlet ports by a
third channel.
Non-limiting examples of inkjet containers also include inkjet
reservoirs such as those disclosed in U.S. Pat. No. 5,818,484 (Lee
et al.); U.S. Pat. No. 5,949,460 (Ahn); U.S. Pat. No. 6,239,822
(Zapata et al.); and U.S. Pat. No. 5,745,137 (Schefflin et al.);
all of which are incorporated by reference herein as if fully
rewritten in their entirety.
Schefflin et al. is incorporated by reference for both an example
of inkjet cartridge structure and inkjet reservoir structure
because Schefflin et al. disclose both.
Using U.S. Pat. No. 6,239,822 (Zapata et al.) as one embodiment of
an inkjet reservoir, four off-carriage ink reservoirs are
identified in the specification and the drawings. The off-carriage
reservoirs are structured to connect with the corresponding print
cartridges via shut-off valves.
Persons having ordinary skill in the art of constructing inkjet
containers, without undue experimentation, can recognize the use of
a polymer compound which contains an oxygen scavenging
composition.
Referring now to FIG. 1, an illustrative embodiment of one
schematic inkjet supply system 10 according to U.S. Pat. No.
5,818,484 (Lee et al.) is depicted including an inkjet printer or
plotter 11 and corresponding print head 12, fluid line 14 and ink
supply container 20. Also depicted in FIG. 1 is a fixed datum
plane, h.sub.0, which serves as a reference point for describing
operation of the system 10.
Container 20 holds a supply of ink 22 having a free surface 24
located a distance h.sub.i, above the datum h.sub.0. The bottom of
the container 20 is located a distance h.sub.c above the datum
h.sub.0. The container 20 is preferably open to ambient pressure
through an opening such as 26 depicted in FIG. 1. Opening 26 also
preferably allows for refilling of the container 20 as ink 22 is
consumed during printing.
Fluid line 14 is provided to supply ink 22 from container 20 to the
print head 12. Typically, it is preferred that fluid line 14
comprise a relatively small diameter tubing to reduce the amount of
ink in the fluid line 14. In one illustrative embodiment, the fluid
line 14 has an inside diameter of about 3.175 mm Those skilled in
the art will, however, be able to select tubing with the
appropriate inside diameter for their printing systems using known
methods.
As shown in FIG. 1, it is preferred to draw ink 22 out of container
20 at a low point to allow for proper operation of the system down
to the lowest levels of ink 22 in the container 20. Higher
placement of the outlet is possible, but may require more frequent
refilling of container 20. Furthermore, although the outlet is
shown as located on the side of the container 20, it will be
understood that the outlet could be provided as a stand pipe with
its opening located near the bottom of the container 20.
The print head 12 is located a fixed distance of h.sub.p above the
datum h.sub.0 and is typically mounted in a printer or plotter for
movement in a horizontal direction across a substrate such as paper
or film. As a result, although the print head 12 moves to
accomplish a printing operation, its distance h.sub.p above the
datum h.sub.0 remains fixed. The print head 12 is located a
distance of h.sub.L above the free surface 24 of the ink 22.
One important feature of the Lee et al. invention is that it
provides the ability to maintain the distance between the print
head 12 and free surface 24 of the ink 22 in container 20, i.e.,
h.sub.L, substantially constant by supporting the container 20 in a
manner such that as ink 22 is removed from container 20, the
container 20 itself is moved with respect to both the print head 12
and the datum h.sub.0. As a result, the static pressure head
between the ink 22 and the print head 12 (determined by the
distance h.sub.L) remains substantially constant throughout the
printing process, both when ink 22 is being consumed and when ink
22 is being added to the container 20 (or if a fill container 20
replaces a nearly empty container).
FIG. 2 is a perspective view illustrating a print cartridge body
100 according to an embodiment of U.S. Pat. No. 6,851,800 (Seu). An
interior 104 of print cartridge body 100 is divided into
compartments (or ink reservoirs) 106, 108, and 110, each for
containing a different colored ink. In one embodiment, compartments
106, 108, and 110 are located side-by-side and are substantially
parallel to each other, as shown in FIG. 1.
As illustrated in FIG. 3, a bottom perspective view of print
cartridge body 100, print cartridge body 100 has a print head die
mounting region 210 surrounding outlet ports 220, 230, and 240 of
print cartridge body 100. In one embodiment, print head die
mounting region 210 and outlet ports 220, 230, and 240 are located
on a wall 111 of print cartridge body 100. Outlet ports 220, 230,
and 240 are aligned on a single axis 250 that is substantially
perpendicular to a direction of motion of cartridge print body 100
during printing, as indicated by arrow 260.
More specifically, in one embodiment, print cartridge body 100
includes opposing walls 112 and 114. Opposing walls 112 and 114 are
connected between opposing walls 116 and 118 and are substantially
perpendicular to opposing walls 116 and 118. Opposing walls 112 and
1114 and opposing walls 116 and 118 define interior 104 of print
cartridge body 100. In one embodiment, opposing walls 112 and 114
and opposing walls 116 and 118 are substantially perpendicular to
wall 111. Partitions 130 and 132 are disposed within interior 104
and define compartments 106, 108, and 110. In one embodiment,
partitions 130 and 132 are substantially parallel to each other and
are substantially parallel to walls 116 and 118. Compartment 106 is
located between wall 116 and partition 130, compartment 108 between
partitions 130 and 132, and compartment 110 between partition 132
and wall 118.
Further, as shown in FIG. 2 for one embodiment, a stepped divider
150 separates channels 123 and 125 and enables channels 123 and 125
to overlap.
A channel 123 interconnects cavity 122 and a channel 430. Channel
430 passes through print cartridge body 100 to connect channel 123
to an outlet port 220.
A channel 125 interconnects cavity 124 and a channel 630, as shown
in FIG. 2. Channel 630 passes through print cartridge body 100 to
connect channel 125 to an outlet port 220.
Polymer Resin for Inkjet Container
Any thermoplastic resin can be a candidate for forming into a
plastic article, such as inkjet container as defined above.
The thermoplastic resin is a matrix containing other ingredients,
such as the oxygen scavenging composition, and can be formed by
molding, extruding, calendering, three dimensional printing,
thermoforming, etc. into the final shape of the inkjet container.
Other materials identified in the patents reference above can be
added to provide the completed assembly of the inkjet container so
desired. Indeed, an advantage of the invention is that the
structure and function of the inkjet container is unchanged, except
for the addition of the oxygen scavenging composition in the
thermoplastic resin to provide protection against oxidation of the
ink.
Non-limiting examples of thermoplastic resins useful in this
invention are polyesters (including polylactides and
polyhydroxyalkanoates), polyamides, polyolefins, polycarbonates,
polystyrenes, polyacrylates, thermoplastic elastomers (including
thermoplastic vulcanizates) of all types, and the like.
Because the shelf-life of inkjet ink needs protection from the
oxidizing effect of reactions with oxygen molecules within or
penetrating the inkjet containers, the selection of the
thermoplastic resin to be used as the matrix in the present
invention is predicated on cost, performance, appearance, and other
considerations already inherent in the inkjet printing
industry.
Of the polymeric candidates, polyesters and polyethylene are
preferred. Of them, polyesters are particularly preferred. While
many inkjet containers are made of the more expensive polybutylene
terephthalate (PBT), the addition of the oxygen scavenging
composition can permit the use of the less expensive polyethylene
terephthalate (PET), virginal or recycled, as the thermoplastic
resin for the matrix forming the inkjet container. Additionally,
thermoplastic elastomers are preferred for use as closures or
closure liners or gaskets or seals or other constructions which are
a part of a conventional inkjet container.
Oxygen Scavenging Composition
Any oxygen scavenging composition is a candidate for use in this
invention. The mechanism of scavenging is based on the composition
having chemical properties which are ready for reaction with oxygen
molecules.
The amount of oxygen scavenging composition to be present in the
polymer resin for the inkjet container is a function of the size of
the container, the amount of ink, the amount of oxygen of any of
three types identified above, and the duration of storage desired.
Without undue experimentation, a person having ordinary skill in
the art can make a determination of the sufficiency of any
particular amount of oxygen scavenging composition depending on the
type of oxygen scavenging composition to be employed. Without
limitation, four different types are identified here as useful.
Copolymer of Polycondensate Segments and Oxygen Scavenging Moiety
Segments
One type of oxygen scavenging composition is typified by U.S. Pat.
No. 7,214,415 (Tibbett et al.), incorporated by reference herein as
if fully rewritten in its entirety. The oxygen scavenging
composition is comprised of a modified copolymer comprised of
predominantly polycondensate segments containing a lesser weight
percentage of oxygen scavenging moiety (OSM) segments. The OSM
segments need only be present in an amount necessary to provide the
degree of oxygen scavenging capacity needed for the particular
application.
The OSM segments of the oxygen scavenging copolymers are at least
singly functionally terminated with a group capable of entering
into polycondensation polymerization and/or capable of reaction
with previously formed polyester moieties to form new covalent
bonds. Alternately, these OSM segments can react with the polymer
end groups to provide a copolymer structure. A functionally
terminated OSM may be represented by Formula 1. X-(OSM)-Y Formula
1
Double functionality is shown in Formula 1 as one possibility but
the OSM may be singly functionally terminated or functionalized to
a degree greater than two. Those persons having ordinary skill in
the art will recognize that the commercial availability of
functionally terminated OSM species will obviate the need to add
such functionalization. An essential feature of the OSM of Formula
1 is that it is readily oxidizable at ambient temperature, and this
auto-oxidation does not result in the generation of significant
volatile or extractable by-products.
Preferred OSM's include polyolefin oligomers of molecular weight
100 to 10,000, polypropylene oxide oligomers, or methyl pendant
aromatic compounds as defined in U.S. Pat. No. 6,346,308 (Cahill et
al.), incorporated by reference herein as if fully written in its
entirety. The polybutadiene moiety, when incorporated as segments
in a modified copolymer, serves as a suitable OSM. However,
especially preferred is the unhydrogenated polybutadiene oligomer
of MW 1000-3,000. In Formula 1, X and Y are typically the same and
may be any species capable of entering into polycondensation and/or
transesterification. A non-limiting list of possible species
represented by X or Y includes OH, COOH, NH.sub.2, epoxides, and
substituted derivatives thereof capable of entering into
step-growth, condensation and/or transesterification reactions.
Oxygen Scavenging Unsaturated Polymer
A second type of oxygen scavenging composition is typified by a
reducing agent for oxygen molecules comprising a polymer formed
from a base component, an unsaturated polymeric reducing component,
and, optionally, a linking component, such as disclosed in U.S.
Patent Application Publication 20120100263 (Hu et al.),
incorporated by reference herein as if fully written in its
entirety. More particularly, the unsaturated polymer is the
polymerization product of macrocyclic poly(alkylene dicarboxylate)
oligomer, unsaturated functional polymer, and, optionally
epoxy-functional styrene-acrylate oligomer. Non-limiting examples
of unsaturated functional polymeric reducing components include
hydroxyl- or glycidyl-functional polyalkenes or polyalkynes, such
as a hydroxyl-terminated polybutadiene or an epoxy functionalized
hydroxyl-terminated polybutadiene. Of these examples, a
commercially available hydroxyl-terminated polybutadiene is
preferred because it is a colorless liquid amenable to use in
reactive extrusion polymerization and has a number average
molecular weight of about 2800 with approximately 20% of the
backbone being vinyl double bonds (CAS #69102-90-5). Hu et al.
discloses a terpolymer, but the present invention could also
benefit from a copolymer of macrocyclic poly(alkylene
dicarboxylate) oligomer and unsaturated functional polymer.
Terpolymers synthesized according to Hu et al. or copolymers
identified in the preceding paragraph are unsaturated
macromolecules capable of reacting with oxygen molecules and
scavenge for those oxygen molecules at the surface of the article
in which such macromolecules reside and within the bulk of the wall
itself. A benefit of use of macromolecular polymers is that they
are not themselves volatile or mobile within the volume contained
by thermoplastic article holding inkjet ink. Macromolecules do not
migrate from the thermoplastic compound.
The combination of the base component, the unsaturated functional
polymeric reducing component, and, optionally, the linking
component to form the polymer makes it suitable for use in inkjet
containers because the polymer is compatible with the thermoplastic
matrix of the plastic article in order to provide good dispersion
therein. Alternatively, the polymer has good compatibility at a
molecular level with the thermoplastic matrix to optimize clarity
and translucency. Most preferably, the polymer is miscible with the
thermoplastic matrix.
The oxygen scavenging properties of the unsaturated polymer arise
from the presence of carbon-carbon unsaturated bonds remaining as
an unreacted part of the unsaturated functional polymeric reducing
component after polymerization of the polymer. These carbon-carbon
unsaturated bonds are susceptible to reaction with oxygen
molecules. Indeed, whereas other uses of such macromolecules as
polymers might be seen as decaying in the presence of oxygen, their
use as an oxygen scavenging additive to the thermoplastic matrix is
beneficial in the present invention.
The polymer benefits from catalysis of the two or three components
during polymerization. A commercially available catalyst can be
used. Presently preferred is an organic titanate such as titanium
tetrakis(2-ethylhexanolate) (CAS #1070-10-6).
The polymer can accommodate a wide variety of amounts of the two or
three components, but it has been found that a plurality, and
preferably a majority of unsaturated functional polymeric component
is preferred because the oxygen scavenging capacity is directly
related to the number of unreacted carbon-carbon unsaturated bonds
available for reducing oxygen and eliminating it from the interior
volume of the plastic packaging article.
The polymer is macromolecular and not susceptible to migration or
"blooming" from the bulk of the plastic article to a surface of the
plastic article but have unsaturated carbon-carbon moieties which
are vulnerable to oxidation by free oxygen molecules which come
into contact with them, whether within the bulk of the plastic
packaging article wall or on the surface of that wall. In effect,
this vulnerability becomes the reducing agent of the macromolecular
polymer and each oxygen molecule-unsaturated carbon bond reaction
is a scavenging event for mobile oxygen molecules within an inkjet
container as defined above made using polymers of the present
invention.
The polymer can be mixed into the thermoplastic matrix alone, but
the compound preferably benefits from the use of an oxidation
catalyst, one that assists the reduction reaction with oxygen.
Indeed, when a catalyst is to be used, it is possible for the
catalyst to be pre-mixed into the thermoplastic matrix before
compounding with the polymer or pre-mixed into a masterbatch
carrier before molding with the polymer and the thermoplastic
matrix.
Catalysts can help activate the unsaturated reducing agent
component of the polymer. Catalysts are not required, but they are
preferred. If present, they can be photo-activated catalysts,
moisture-activated catalysts, heat-activated catalysts, etc., all
well known to a person having ordinary skill in the art.
Unsaturated polymers of this second type can proceed in the
scavenging for oxygen without the need for catalysis. For example,
inkjet containers which are formed at or near the same time as the
filling of that container with inkjet ink can benefit from such
oxygen scavenging agents that do not need activation to begin
reducing oxygen molecules.
However, for one particular industry serving as an example for
persons skilled in the art of making inkjet containers, it is quite
important for the unsaturated polymer, functioning as the reducing
agent for oxygen molecules, to remain dormant until container
formation. Beverage bottles and other liquid containers are often
made in two steps, one to form a so-called "pre-form" which has the
final dimensions of the opening but is collapsed with respect to
the final volume; and the second to mold the pre-form into a
container, vessel, or bottle of final dimensions. For example,
water, soft drink, and beer bottles start as pre-forms with the
proper dimensions of the screw cap mouth and a highly collapsed
remainder resembling a deflated bottle or a truncated test tube. At
the bottling factory, the pre-forms are expanded by blow molding to
form liter or half liter bottles just prior to beverage
filling.
The relative dormancy of the oxygen scavenging function of the
polymer is important for the beverage industry because one does not
want to waste the oxygen scavenging properties on a pre-form
exposed to the environment during storage, prior to blow molding
and filling. Therefore, for this industry in particular, and any
other which relies on pre-formed partially completed containers,
the onset of oxygen scavenging needs to be triggered by an event
after the formation of the pre-form.
Non-limiting examples of catalysts are transition metals
(heat-activated) and benzophenones (photo-activated). The
concentration of catalyst relative to polymer can be as little as
10 parts per million of polymer to contribute to oxygen
scavenging.
Of the catalysts, transition metal salts are most preferred because
they are thermally activated. Such salts include those of cobalt,
cerium, manganese, etc. These types of catalysts are suitable for
activation of the polymer to function as a macromolecular oxygen
reducing agent at the time of formation of the pre-form into a
blow-molded bottle, which happens at elevated heat to melt the
pre-form for ultimate shaping.
A non-limiting example of a commercially available catalyst is
cobalt stearate (CAS #13586-84-0) to serve as a catalyst for the
oxidation of the oxidizable organic compounds.
Oxygen Scavenging Dendrimers
A third type of oxygen scavenging composition is typified by oxygen
scavenging dendrimers such as those disclosed in U.S. Patent
Application Publication No. 20120070545 (Hu et al.), incorporated
by reference herein as if fully rewritten in its entirety. More
particularly, the oxygen scavenging composition is an amphiphilic
dendritic polymer ("dendrimer") functioning as a reducing agent for
oxygen molecules.
The usefulness of this dendrimer is its locations of unsaturation
on the hydrophobic chains.
As further reported by its manufacturer, Perstorp, Boltorn.TM.
W3000 dendritic polymer is a non-ionic, self-emulsifying
amphiphilic dendritic polymer, consisting of a dendritic globular
structure from which chain ends are terminated by a combination of
hydrophobic chains (long unsaturated fatty acid allowing air drying
oxidation process) and hydrophilic chains (methyl polyethylene
glycol chains).
The amphiphilic nature of this dendritic polymer confers some
dispersing and stabilizing properties. This behavior is used to
disperse conventional alkyd resins (initially prepared for solvent
borne systems) in water. A core/shell particle type of emulsion is
obtained, the core being the alkyd resin that controls the coating
properties and the shell being the amphiphilic dendritic polymer.
BOLTORN.TM. W3000 polymer is made from a pentaerythritol derivative
which still has 4 alcohols able to build layers with
dimethylproprionic acid (DMPA) and get the hyperbranched polyester
morphology (i.e., its dendrimer structure) which then is
functionalized, followed by being capped with methyl polyethylene
glycol (MPEG) and some hydrophobic sunflower fatty acid.
The dendrimer is macromolecular and not susceptible to migration or
"blooming," especially because of its amphiphilic nature.
The dendrimer is particularly advantageous in use as a reducing
agent for oxygen molecules is because its dendritic structure makes
many unsaturated carbon-carbon bonds available for oxidation, per
unit volume of dendrimer. These unsaturated carbon-carbon bonds are
vulnerable to oxidation by free oxygen molecules which come into
contact with them, whether within the bulk of the plastic packaging
article wall or on the surface of that wall. In effect, this
vulnerability becomes the reducing agent of the macromolecular
dendrimer and each oxygen molecule--carbon-carbon double bond
reaction is a scavenging event for mobile oxygen molecules within a
food or beverage container or package made using the
dendrimers.
As with the second type of oxygen scavenging composition, an
optional catalyst can be used to help activate the hydrophobic
chains of the dendrimer. The catalysts mentioned for the oxygen
scavenging unsaturated polymer are also useful for the oxygen
scavenging dendrimer.
Molecular Hydrogen Generator
A fourth type of oxygen scavenging composition is typified by a
hydrogen generating means disclosed in U.S. Patent Application
Publication 20100028499 (Rule et al.), incorporated by reference
herein as if fully rewritten in its entirety.
Long-term protection from oxygen ingress can be provided to
permeable inkjet containers by inclusion of a hydrogen generating
means which may comprise one or more components that slowly release
molecular hydrogen inside the container over an extended period of
time. In the presence of a suitable catalyst, the molecular
hydrogen will react with any oxygen present in the interior of the
container or in the container wall. Preferably, the rate of
hydrogen release is tailored to match the rate of oxygen ingress
into the container. In addition, it is preferable for there to be
an initial relatively rapid release of hydrogen, followed by a slow
continual release over a period of months or even years.
Furthermore, it is preferred that substantial release of hydrogen
reliably begins only when the inkjet container is filled. Finally,
it is preferable that the substance releasing hydrogen does not
adulterate the contents of the container.
The container may include a sidewall constructed from a composition
that includes a polymer resin first component described above and a
second component comprising a catalyst capable of catalyzing a
reaction between molecular hydrogen and molecular oxygen. The
container may also include a third component capable of releasing
molecular hydrogen for an extended period of time. The third
component is preferably located within the container or near an
interior surface of the container. The component capable of
releasing molecular hydrogen is preferably located in or on a
closure of the container. Suitably, the component capable of
releasing molecular hydrogen comprises an active substance that
releases molecular hydrogen by reaction with moisture.
The polymeric matrix may include at least 1 wt % of active
substance to generate hydrogen, preferably at least 2 wt %. The
polymeric matrix may include less than 16 wt % of active substance.
Suitably, the polymeric matrix includes 1-16 wt %, preferably 4-8
wt % of active substance. The balance of material in the polymeric
matrix may predominantly comprise a said polymeric material.
The active substance may comprise a metal and/or a hydride. A said
metal may be selected from sodium, lithium, potassium, magnesium,
zinc or aluminum. A hydride may be inorganic, for example it may
comprise a metal hydride or borohydride; or it may be organic.
Active substances suitable for the release of molecular hydrogen as
a result of contact with water include but are not limited to:
sodium metal, lithium metal, potassium metal, calcium metal, sodium
hydride, lithium hydride, potassium hydride, calcium hydride,
magnesium hydride, sodium borohydride, and lithium borohydride.
While in a free state, all of these substances react very rapidly
with water; however, once embedded into a polymeric matrix, the
rate of reaction proceeds with a half-life measured in weeks to
months. For example, sodium borohydride reacts with pH 7 water with
a half-life of less than about 5 seconds at 22 deg C. However, at
22.degree. C., 4 wt % dispersion of sodium borohydride dispersed in
low density polyethylene (LDPE) exhibits a half-time for hydrogen
generation in excess of 180 days. Even more dramatically, when
dispersed into LDPE, sodium hydride releases hydrogen over a period
of months, whereas the dry powder ignites on exposure to water, and
even a 60% oil dispersion of sodium hydride will release hydrogen
violently.
Other active substances may include organic hydrides such as
tetramethyl disiloxane and trimethyl tin hydride, as well as metals
such as magnesium, zinc, or aluminum. Where the rate of reaction
between the active substance and water is too slow, the addition of
hydrolysis catalysts and/or agents are explicitly contemplated. For
example, the rate of hydrolysis of silicon hydrides may be enhanced
by the use of hydroxide or fluoride ions, transition metal salts,
or noble metal catalysts.
In order to facilitate the reaction between molecular hydrogen with
molecular oxygen, a catalyst is desired. A large number of
catalysts are known to catalyze the reaction of hydrogen with
oxygen, including many transition metals, metal borides (such as
nickel boride), metal carbides (such as titanium carbide), metal
nitrides (such as titanium nitride), and transition metal salts and
complexes. Of these, Group VIII metals are particularly
efficacious. Of the Group VIII metals, palladium and platinum are
especially preferred because of their low toxicity and extreme
efficiency in catalyzing the conversion of hydrogen and oxygen to
water with little or no byproduct formation. The catalyst is
preferably a redox catalyst.
Optional Additives
The compound of the present invention can include conventional
plastics additives in an amount that is sufficient to obtain a
desired processing or performance property for the compound. The
amount should not be wasteful of the additive nor detrimental to
the processing or performance of the compound. Those skilled in the
art of thermoplastics compounding, without undue experimentation
but with reference to such treatises as Plastics Additives Database
(2004) from Plastics Design Library (elsevier.com), can select from
many different types of additives for inclusion into the compounds
of the present invention.
Non-limiting examples of optional additives include adhesion
promoters; biocides (antibacterials, fungicides, and mildewcides),
anti-fogging agents; anti-static agents; bonding, blowing and
foaming agents; compatibilizers; dispersants; fillers and
extenders; fire and flame retardants and smoke suppresants; impact
modifiers; initiators; lubricants; micas; nucleants; pigments,
colorants and dyes; plasticizers; processing aids; release agents;
silanes, titanates and zirconates; slip and anti-blocking agents;
stabilizers; stearates; ultraviolet light absorbers; viscosity
regulators; waxes; and combinations of them.
Processing
The preparation of compounds of the present invention is
uncomplicated. The compound of the present can be made in batch or
continuous operations.
Mixing in a continuous process typically occurs in an extruder that
is elevated to a temperature that is sufficient to melt the polymer
matrix with addition either at the head of the extruder or
downstream in the extruder of the solid ingredient additives.
Extruder speeds can range from about 50 to about 500 revolutions
per minute (rpm), and preferably from about 100 to about 300 rpm.
Typically, the output from the extruder is pelletized for later
extrusion or molding into polymeric articles.
Mixing in a batch process typically occurs in a Banbury mixer that
is also elevated to a temperature that is sufficient to melt the
polymer matrix to permit addition of the solid ingredient
additives. The mixing speeds range from 60 to 1000 rpm and
temperature of mixing can be ambient. Also, the output from the
mixer is chopped into smaller sizes for later extrusion or molding
into polymeric inkjet containers or parts of them.
Subsequent extrusion or molding techniques to make inkjet
containers or parts of them are well known to those skilled in the
art of thermoplastics polymer engineering. Without undue
experimentation but with such references as "Extrusion, The
Definitive Processing Guide and Handbook"; "Handbook of Molded Part
Shrinkage and Warpage"; "Specialized Molding Techniques";
"Rotational Molding Technology"; and "Handbook of Mold, Tool and
Die Repair Welding", all published by Plastics Design Library
(www.williamandrew.com), one can make articles of any conceivable
shape and appearance using compounds of the present invention.
Usefulness of the Invention
Inkjet ink containers are ubiquitous in personal and business
locations. From a desktop inkjet printer in a home or office to a
large format inkjet printer in a commercial printing establishment,
the freshness of the inkjet ink can be protected by the use of
polymer compounds described above using any of the four types of
oxygen scavenging compositions.
The invention is not limited to the above embodiments. The claims
follow.
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